Emission Enhancement and Energy Transfers in YV0.5P0.5O4 Nanoparticles Codoped with Eu3+ and Bi3+ Ions.

In this study, solid-state solutions of yttrium orthovanadate-phosphate with varying concentrations of codopants (Eu3+, Bi3+) have been obtained via coprecipitation. An ionic radii mismatch between V5+ and P5+ substituents is manifested in broad XRD lines. The sharpening of the XRD lines is observed with increasing bismuth ions concentration in the Eu3+ codoped YV0.5P0.5O4 matrix. The difference in the number of the Stark components for the 5D0 → 7FJ transitions indicates changes in the lattice and a number of possible Eu3+ sites. A thorough, systematic spectroscopic analysis of YV0.5P0.5O4: x mol % Eu3+, y mol % Bi3+ was conducted at room temperature and 5 K. Metal-to-metal energy transfers occurring between Eu3+, V5+, and Bi3+ optically active ions have been investigated. Additionally, efficiency of the Bi3+-Eu3+ energy transfer (ET) was calculated.

Forgotten and Resurrected Chernovite-(Y): YAsO4 Doped with Eu3+ Ions as a Potential Nanosized Luminophore.

In the present work, a precipitation method was employed to prepare nanosized YAsO4 doped with Eu3+ ions. The raw nanomaterials have been thermally treated in a temperature range between 500 and 900 °C for 3 h. The XRD analysis demonstrated that the powders were single-phase nanopowders with high crystallite dispersion. Our studies were focused on relating the luminescence properties of the Eu3+ dopant to the nanocrystallite (NC) size. The average NC size varied accordingly between 15 and 45 nm. We have found that the size effect is manifested mainly in the expansion of the cell volume and broadening of XRD peaks, as indicated by Rietveld analysis. Moreover, the emission and excitation spectra, although typical for Eu3+ ions, demonstrated some degree of variability with calcination temperatures and doping concentration. To explain these differences, a detailed analysis of luminescence spectra by the Judd-Ofelt theory has been performed.

The Safety of Fluoride Compounds and Their Effect on the Human Body-A Narrative Review.

Fluoride is one of the elements commonly present in the human environment. Due to its characteristics, it is very widely used in medicine, dentistry, industry or agriculture. On the other hand, its universality possesses a real threat to the human body in the form of acute and chronic poisoning. The aim of this paper is to characterize the properties of fluoride and its effects on the human body, as well as the sources of its occurrence. Particular emphasis is placed on the safety of its use and optimal dosage intake, which prevents accumulation and reduces its potential side effects. The positive effect of proper fluoride supply is widely described. In order to avoid overdose, it is best to consult a specialist to properly select the dosage.

An in vitro examination of fluoride ions release from selected materials - resin-modified glass-ionomer cement (Vitremer) and nanohybrid composite material (Tetric EvoCeram).

The aim of this study was to examine a short-term fluoride ions release from selected materials - resin-modified glass ionomer -Vitremer (3M ESPE) and nanohybrid universal composite - Tetric EvoCeram (IvoclarVivadent). Release of fluoride ions [µg/mm2 /h] from Tetric EvoCeram and Vitremer into nine environments (artificial saliva - AS, deionized water and 0.9% NaCl) differing in composition of the solution and pH was determined. Six samples were prepared for each solution. In the short-term study, the measurements were taken after 1, 3, 24, 48, 72 and 168 hours. The cumulative values as well as levels of fluoride ions released at concrete time intervals were compared. Within 7 days (168 hours), both materials showed variable levels of fluoride ions release. The highest value of fluoride ions release from nanohybrid Tetric EvoCeram material was reported in deionized water (8) after 24 hours (1.550 ± 0.014 [µg/mm2/h]) and the lowest value was read in the artificial saliva AS pH 7.5 (5) after 1 hour (0.022 ± 0.001 [µg/mm2/h]). What's more, the highest value of F- release from Vitremer was found in deionized water (8) after 168 hours of immersion (24.021 ± 2.280 [µg/mm2/h]) and the lowest value was in the artificial saliva AS (without Ca2+) pH 4.5 (6) (0.303 ± 0.249 [µg/mm2/h]) after 168 hours. Cumulated release of F- after 7 days was notably higher from resin- modified glass ionomer material - Vitremer in all artificial saliva solutions (1-7) which imitated the environment of oral cavity. Therefore, we can assume that Vitremer has better remineralization potential and it may constitute a more effective method of tooth decay prevention.

Structural and Luminescence Behavior of Nanocrystalline Orthophosphate KMeY(PO4)2: Eu3+ (Me = Ca, Sr) Synthesized by Hydrothermal Method.

KMeY(PO4)2:5% Eu3+ phosphates have been synthesized by a novel hydrothermal method. Spectroscopic, structural, and morphological properties of the obtained samples were investigated by X-ray, TEM, Raman, infrared, absorption, and luminescence studies. The microscopic analysis of the obtained samples showed that the mean diameter of synthesized crystals was about 15 nm. The KCaY(PO4)2 and KSrY(PO4)2 compounds were isostructural and they crystallized in a rhabdophane-type hexagonal structure with the unit-cell parameters a = b ≈ 6.90 Å, c ≈ 6.34 Å, and a = b ≈ 7.00 Å, c ≈ 6.42 Å for the Ca and Sr compound, respectively. Spectroscopic investigations showed intense 5D0 → 7F4 transitions connected with D2 site symmetry of Eu3+ ions. Furthermore, for the sample annealed at 500 °C, europium ions were located in two optical sites, on the surface of grains and in the bulk. Thermal treatment of powders at high temperature provided better grain crystallinity and only one position of dopant in the crystalline structure. The most intense emission was possessed by the KSrY(PO4)2:5% Eu3+ sample calcinated at 500 °C.

Evaluation of the microbial, cytotoxic and physico-chemical properties of the stainless steel crowns used in pediatric dentistry.

Preformed stainless steel crowns are used in pediatric dentistry to obtain full crown restoration of primary molar teeth. They are consider the best restoration in terms of durability and effectiveness. The purpose of this study is to evaluate microbial, cytological and physio-chemical properties to determine whereas stainless steel crown are biocompatible, safe for surrounding tissue and helpful in avoiding micro-organisms influence on the tooth tissue. Based on the results, it was determined that stainless steel crowns used in pediatric dentistry represent no cytotoxic risk to the surrounding tissues, have a low probability of developing hypersensitivity to the coronal material and also that their biological properties make them suitable to use in pediatric dentistry for the reconstruction of damaged primary molar tissue.

The study of the influence of pH on the structural and spectroscopic properties of nanocrystalline Eu3+ ion-doped yttrium orthovanadate.

In this study, it has been presented the influence of pH conditions on the evolution of the size, morphology and spectroscopic properties of yttrium orthovanadate during synthesis. A thorough research on the spectroscopic properties was performed. A series of highly crystalline 1 mol% Eu3+:YVO4 has been synthesized via the co-precipitation method. In addition, to improve the crystallinity, the materials were heat-treated at 800 °C, and the structural and morphological properties of the particles were studied using XRD (X-ray powder diffraction) and SEM (Scanning Electron Microscopy) techniques. In order to investigate the spectroscopic properties of 1 mol% Eu3+:YVO4, emission spectra and luminescence kinetics were measured. It was found that alkaline pH manifests in smaller particles compared to acidic pH conditions. In addition, superior spectroscopic properties were observed in materials obtained in alkaline pH.

Quenching of the Eu3+ Luminescence by Cu2+ Ions in the Nanosized Hydroxyapatite Designed for Future Bio-Detection.

The hydroxyapatite nanopowders of the Eu3+-doped, Cu2+-doped, and Eu3+/Cu2+-co-doped Ca10(PO4)6(OH)2 were prepared by a microwave-assisted hydrothermal method. The structural and morphological properties of the products were investigated by X-ray powder diffraction (XRD), transmission electron microscopy techniques (TEM), and infrared spectroscopy (FT-IR). The average crystal size and the unit cell parameters were calculated by a Rietveld refinement tool. The absorption, emission excitation, emission, and luminescence decay time were recorded and studied in detail. The 5D0 → 7F2 transition is the most intense transition. The Eu3+ ions occupied two independent crystallographic sites in these materials exhibited in emission spectra: one Ca(1) site with C3 symmetry and one Ca(2) sites with Cs symmetry. The Eu3+ emission is strongly quenched by Cu2+ ions, and the luminescence decay time is much shorter in the case of Eu3+/Cu2+ co-doped materials than in Eu3+-doped materials. The luminescence quenching mechanism as well as the schematic energy level diagram showing the Eu3+ emission quenching mechanism using Cu2+ ions are proposed. The electron paramagnetic resonance (EPR) technique revealed the existence of at least two different coordination environments for copper(II) ion.

In Vitro Studies concerning Selected Properties of a Composite Material Blended with Nanofluoroapatite Crystals.

The aim of the paper was to determine the potential for fluorine release from an original composite material blended with nanofluoroapatite (FAp). The level of fluoride ion emission into deionized water and saline was studied over a period of 12 weeks. Values were recorded after 1, 3, 24, 48, 72, and 96 h and then weekly for a period of 12 weeks. There were statistically significant differences in the periods of fluoride ion release from 5%FAp and 2%FAp materials into saline solution as well as into deionized water. The highest fluorine release from 5%FAp + polymer was observed in the 10th and 11th week of incubation (for saline solution) and in the 9th, 10th, and 11th week (for deionized water). The highest fluorine release from 2%FAp + polymer was observed in the 9th, 11th, and 12th week of incubation for both environments. Total fluoride ion release from 5%FAp + polymer and mean fluoride release levels were similar in 5%FAp and 2%FAp in both environments. Both tested materials (5%FAp and 2%FAp) show the ability to release fluoride ions over a long time in the experimental environment.

Assessment of Microstructure and Release of Fluoride Ions from Selected Fissure Sealants: An In Vitro Study.

The aim of this study was to compare fluoride release from four selected fissure sealants: fissure sealant manufactured by Arkona, Helioseal F, Helioseal F Plus, and Conseal. Tested parameters included emission of fluoride ions into saline (0.9% NaCl) and deionized water over a period of 2 weeks. Values were recorded after 1, 3, 24, 48, 72, and 96 h, and then after 1 and 2 weeks. All sealants were characterized by a constant fluoride release level. The highest fluoride release level was noted for Conseal (0.0169 ppm/mg), while the lowest was noted for fissure sealant manufactured by Arkona (0.063 ppm/mg). Fissure sealants, which contain fluoride, release it not only during polymerization, but also for several days after application. The use of fissure sealants whose composition includes fluoride is an effective method of preventing tooth decay.

Preliminary In Vitro Study of Fluoride Release from Selected Ormocer Materials.

The purpose of the in vitro study presented in this paper was to determine the long-term release of fluoride ions from selected ormocer materials (Admira (A), Admira Flow (AF), Admira Seal (AS)). The release of fluoride ions from these materials into a saline solution (0.9% NaCl) and deionized water was tested for 14 weeks. In a long-term study the measurements were taken after 1 and 3 h, then 1, 2, and 3 days and then at weekly intervals for 14 weeks. In a short-term study the measurements were made after 3, 24, 48, 72, 69, 168 h, i.e., within 7 days. All materials used in the test showed a constant level of fluoride release. The highest level of cumulative release of fluoride ions into deionized water was found in the AS material (23.95 ± 4.30 µg/mm2), slightly lower in the A material (23.26 ± 4.16 µg/mm2) and the lowest in the AF material (16.79 ± 2.26 µg/mm2). The highest level of cumulative release into saline solution was found in AF (8.08 ± 1.30 µg/mm2), slightly lower in AS (7.36 ± 0.30 µg/mm2) and the lowest in A (6.73 ± 1.10 µg /mm2). After 1 h of immersion of the samples in the saline solution, the highest level of fluoride was released by AF (0.57 ± 0.06 µg/mm2) followed by A (0.20 ± 0.03 µg/mm2) and AS (0.19 ± 0.02 µg/mm2). Moreover, in the 14-week study, the total amount of fluoride release into the saline, which imitates the environment of the oral cavity, was observed as the highest in the AF sample.

Strontium Phosphate Composite Designed to Red-Emission at Different Temperatures.

Eu3+-doped Sr10(PO4)6(OH)2-Sr3(PO4)2 (SrHAp-TSP) composites were obtained via the microwave-stimulated hydrothermal method and post-heat-treated from 750 to 950 °C. Concentration of the Eu3+ ions was set to be 0.5, 1, 2, 3, 5 mol% in a ratio of the strontium ions molar content. The structural and morphological properties were investigated by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FT-IR) techniques. The average particle size of the studied materials annealed at 750, 850 and 950 °C were counted about 100, 131 and 173 nm, respectively. The luminescence properties depending on the dopant ion concentration, heat-treatment temperature, excitation wavelength and temperature were investigated. In the emission spectra, a broad peak corresponding to the 4f65d1 → 4f7 (8S7/2) emission of Eu2+ ions as well as narrow 4f-4f transitions typical for Eu3+ ions can be observed. The luminescence intensity of the 1 mol% Eu3+:Sr10(PO4)6(OH)2-Sr3(PO4)2 was measured depending on the ambient temperature in the range of 80-550 K. The CIE 1931 (International Commission on Illumination) chromaticity diagram was determined from emission spectra measured in 80, 300 and 550 K. The reduction mechanism of the Eu3+ to the Eu2+ was explained by the charge compensation mechanism based on the Kröger-Vink-notation. The decay times were measured and the Judd-Ofelt (J-O) theory was applied to analyze the observed structural and spectroscopic features.

Preparation and Characterization of Self-Assembled Poly(l-Lactide) on the Surface of ß-Tricalcium Diphosphate(V) for Bone Tissue Theranostics.

This work was aimed to obtain and characterize the well-defined biocomposites based on ß-tricalcium diphosphate(V) (ß-TCP) co-doped with Ce3+ and Pr3+ ions modified by poly(l-lactide) (PLLA) with precise tailored chain length and different phosphate to polymer ratio. The composites as well as ß-tricalcium diphosphate(V) were spectroscopically characterized using emission spectroscopy and luminescence kinetics. Morphological and structural properties were studied using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The self-assembled poly(l-lactide) in a shape of rose flower has been successfully polymerized on the surface of the ß-tricalcium diphosphate(V) nanocrystals. The studied materials were evaluated in vitro including cytotoxicity (MTT assay) and hemolysis tests. The obtained results suggested that the studied materials may find potential application in tissue engineering.

Investigation of Pyrophosphates KYP2O7Co-Doped with Lanthanide Ions Useful for Theranostics.

Diphosphate compounds (KYP2O7) co-doped with Yb3+ and Er3+ ions were obtained by one step urea assisted combustion synthesis. The experimental parameters of synthesis were optimized using an experimental design approach related to co-dopants concentration and heattreatment as well as annealing time. The obtained materials were studied with theinitial requirements showing appropriate morphological (X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM)) and spectroscopic properties (emission, luminescence kinetics). Moreover, the effect of Er3+ and Yb3+ ions doped KYP2O7 on morphology, proliferative and metabolic activity and apoptosis in MC3T3-E1 osteoblast cell line and 4B12osteoclasts cell line was investigated. Furthermore, the expression of the common pro-osteogenic markers in MC3T3-E1 osteoblast as well as osteoclastogenesis related markers in 4B12 osteoclasts was evaluated. The extensive in vitro studies showed that KYP2O7 doped with 1 mol% Er3+ and 20 mol% Yb3+ ions positively affected the MC3T3-E1 and 4B12 cells activity without triggering their apoptosis. Moreover, it was shown that an activation of mTOR and Pi3k signaling pathways with 1 mol% Er3+, 20 mol% Yb3+: KYP2O7 can promote the MC3T3-E1 cells expression of late osteogenic markers including RUNX and BMP-2. The obtained data shed a promising light for KYP2O7 doped with Er3+ and Yb3+ ions as a potential factors improving bone fracture healing as well as in bioimaging (so-called in theranostics).

New approach to modification of poly (l-lactic acid) with nano-hydroxyapatite improving functionality of human adipose-derived stromal cells (hASCs) through increased viability and enhanced mitochondrial activity.

The aim of this study was to determine the cytocompatibility of poly (l-lactide) (PLLA) scaffolds fabricated using co-rotating twin screw extrusion technique and functionalized with different concentrations of nano-hydroxyapatite (nHAp). The efforts were aimed on the designing bioactive scaffolds improving the viability and metabolic activity of human adipose-derived multipotent stromal cells (hASCs). The in vitro study was designed to determine the optimal nHAp concentration, based on analysis of hASCs morphology, adhesion rate, as well as metabolic and proliferative potential. Initially, the PLLA filled with three different concentrations of the nHAp were tested i.e. 5%, 10% and 15 wt%. The obtained results indicated that the 10 wt% nHAp in the PLLA (10% nHAp/PLLA) matrices improved the adhesion and proliferation of the hASCs, what was in good agreement with the results of tensile properties of the composites. Further, we performed profound studies regarding the cytotoxicity of 10% nHAp/PLLA. The analysis included the evaluation of the biomaterial influence on viability, apoptosis-related markers expression profile and mitochondrial function. The cytocompatibility of 10% nHAp/PLLA scaffolds toward the hASCs was confirmed. The hASCs propagated on 10% nHAp/PLLA were more viable then those propagated on the plain PLLA. The level of pro-apoptotic markers, i.e. caspase-3 and Bax in cultures on 10% nHAp/PLLA was significantly decreased. Obtained results correlated with higher mitochondrial membrane potential of hASCs in those cultures. The obtained composites may improve therapeutic potential of hASCs via directing their adhesion, enhancing proliferation and viability as well as increasing mitochondrial potential, thus may find potential application in tissue engineering.